Paul, once again you are correct. I looked up the specs and they are 0.50mm @15deg. this is what my pump is set to now.
I have a problem with it now. I think I may have run some water through it or something, though at no particulat point did it behave strangely. It doesn't have the familiar clatter it usually had before I started burning hydraulic transmission fluid, and it is down on power a bit, idles higher, and smokes black at full throttle, though not a lot, but more than before. I wasn't heating my oil up before use, but as it is summer here, it wasn't particularly thick either. Also, it is hard to start now, and won't idle for the first 5~10 seconds. Great. I guess it could either be 1)IP, 2)injectors, or 3)low compression. I can't see how the oil may have burnt the pistons or something like that. Even with fresh diesel, it only clatters a little at idle, and no other time as before. I checked the IP timing and it is right on.
When running, it is down on power a bit as described, but is runnung smooth, on all cylinders ( as per injector line test).

Anyone with some guesses? What does a bit of water do to a IP? I'm guessing that's what it may have been.

Gee, just when the fun was beginning..... <img src="/forums/images/graemlins/evil.gif" alt="" />

Zack--

Well, shucks! But,maybe all is not lost. Lost of engine clatter would usually indicate insufficient timing advance. This, in turn, can be caused by a plugged up fuel filter. This is explained as follows: The lift pump inside the injection pump discharges in a pressure range of about 15 psi to 100 psi, depending on engine speed. This range of pressure is used to position an advance piston against a spring force. If the inlet to the lift pump is restricted it cannot generate enough pressure to advance. This will diminish clatter and cause black smoke at higher throttle settings. Probably will also notice a loss of power.

Only problem with my theory here is that I cannot figure how the idle speed would increase. Is your throttle shaft coming back to the idle stop? If so, then I think that maybe something is gummed up in your pump, not allowing the control sleeve to spill fuel as soon as it should.

If gumming is a problem, it might also have jammed up the timing piston, causing all of your problems above. And you could, then, ignore my entire first paragragh.

It is possible to remove the top of the pump with it in the vehicle so as to inspect the interior for gum or sludge or rust. Or, better yet remove the pump and open it up or take it to your nearest friendly fuel injection shop.

Or, if you find that it is terminal or too expensive, you can try finding another pump.

Hang in there--

Paul

Zack...
Did you have to retard or advance the IP timing to get it to the factory setting???

New filters???

A few thoughts about cold starts.......close off the main fuel line when parked over night (vise grips) ....fuel could be siphoned back to tank........check glow system for 180-200 amp initial draw when cold.....try adding a cetane additive or some diesel (thinning the oil helps).......advancing the IP timing can help.......at this time I would not go over 4? advance (see below)

Paul.....and other members.....
I am now working with different IP timing for better results......I am looking a way to monitor the changes other than seat of the pants.........at this time I am thinking about exhaust temps or maybe a type of knock sensor setup???? any thoughts or suggestions......anyone know typical exhaust temps? I am told that there is a diesel timing light that works off a type of pulse signal from the injector line.....anyone have info about this???

I welcome suggestions.
crossbones

Thanks for the replies, guys.
I had to set the pump back to get the idle back down to around 800rpm. You would think it would idle slower, not faster. A bit dismayed, and besides quite busy (getting the winter firewood ready and other things), I decided to give 'er a "Italian Tune-Up". Hardly a scientific approach, I blasted her up to 4000rpm in a couple of gears, holding her there as I was going uphill. The NA really is useless above 3200rpm, or at least my 2 engines are. I rarely rev it past 3 grand anyway. I figured one of 3 things could happen: 1) it would improve, 2) it would blow up, 3) nothing would change. Well, it did seem to improve a bit. Idles the same. It just feels a bit less lazy.
When I start it, it feels like it isn't getting fuel, like the pump is 1/2 empty or the injector lines are drained. Starts and quits after a bit of cranking. Eventually it runs steady. I have 2 tanks, the stock one with the stock fuel pump in it since over 2 years, and a fuel filter. Good flow of fuel out of the filter with the key on. Second tank in the back of the truck in the box, higher than the injector pump, gravity feed. Separate filter for that one also, with fuel comeing out freely. Besides, if either one were plugged it wouldn't rev up, certainly not to 4000rpm blowing smoke. No visible fuel leaks anywhere. I have been running it off the gravity feed tank, so run-back isn't going to happen, especially with the return higher than the feed. Sucking in air...I don't believe, or again it wouldn't rev up, due to the lack of fuel.
I haven't given up on the alternative fuel idea yet, but I do need to figure out what happened. I'm going to see if I can rebuild my other injectors, then try them. I know they are bad, so fixing them up isn't a bad idea anyway. I have a pump on the other motor, so it may end up going in the truck, though honestly I don't know how "correct" it is, as that motor ran with the bad injectors.

Ahhh yes! the joy of it all! <img src="/forums/images/graemlins/cyclops.gif" alt="" />

Well, for anyone curious about this curious problem, I found the cause.

My comments last night were about the injectors and what to do with them. As this problem was playing on my mind, the more I thought about it, the more I believed it may be injector related. This morning I took an old injector from my other engine into work, and tested it. <img src="/forums/images/graemlins/zombie.gif" alt="" /> BAD! Opened at 1200 PSI, and came out in a pencil stream. No wonder the old engine ran so bad. So I won't be using that one anytime in the near future.
Tonight after supper, I decided to check the injectors anyway, just a visual check. Pulled #1 out, and there was carbon build-up around the center hole. AHA! This of course will prevent a spray pattern and any atomization, and any decent starting too. So I carefully scraped the crap off the injector all around the "needle", and made sure the hole was clean in the heat shield. All the injectors were like this, except #4, which was surprisingly clean. Strange, I thought. Shined a light down the injector hole, saw nothing. That's because it was blocked solid, with the exception of a very small hole in the center. Beats me how this engine ran.

Cleaned everything up, started it up, and the familiar clatter is back. No doubt I have the timing a bit advanced, but it's been like this since 10 months, and besides, it only does it at lower engine speeds and below 1/4 throttle. So I turned the pump back to about where it was before the trouble, adj the idle. Actually runs decent now. I know these injectors were clean before all this because I had them out about a month ago and they were good then. The final test will be a cold start to see if there may be other problems elsewhere.

What exactly caused the problem I'm not sure. I would switch over from diesel about a minute after starting, long before the motor reached operating temps. Now, was it that, or the transhydraulic fluid I was using? The logical guess would be the cold operating temps, yet I did the same thing before with WVO and no problems, though I didn't run as much WVO as I did this transmission/hydraulic fluid. If coking is my only problem, I'm going to run it again, except when the engine is warn, and the the heated lines connected.

Just thought I'd let you know what I found. Maybe it might help someone somewhere.

Zack--

Well, you had me stumped. But glad you sleuthed it out. Is there an explanation in there any place about why the idle speed picked up?

This is very informative and a bit entertaining. Please keep us posted.

Paul

Ok then, the truck runs as it used to. Started this afternoon without glowing it, as before. Has decent power again...or certainly better than it had recently been. Beats me about the idle. All I can figure is it must have something to do with poorly atomized fuel. It wasn't getting any more fuel, just not atomized very well, which explains why I could never seem to set up the other motor properly, with the bad injectors. I think the other motor isn't nearly as bad as I thought. I believe this is the learning curve part. I guess my only excuse is diesel stuff comes to me as an interest without training, just what I read and do. Gee, aren't most hobbies like that?

Which brings me to a question: after opening the old injector, I see the opening pressure can be adjusted very easily, whereas the VW ones were adjusted by shimming the spring (as per the manual), so now I wonder if increasing the opening pressure will help atomization? Has anyone played with this? A fellow at work thinks this is what is done when boosting the HP in a diesel, no doubt with other mods. As I have heard and read of other accounts where guys say they could easily smoke the tires on their diesels (Paul I believe you may know of one fellow I speak of), mine is no where near that, although roasting the tires is not my interest. Clearly, if these claims are accurate, them my truck is really down on power. So anyway, the Isuzu manual mentions starting pressure as 1493 psi. Then on another page it says 1707 psi. And finally on the pump page, it says injection starting pressure is 2133 psi. I guess ya just pick the one you like the most, or something. Whatever.
I'm going to crank the pressure on the old injector tomorrow and see if it sprays properly, and if it does, crank it a bit more and observe.
A simple, reversible adjustment is worth a try in my mind. Especially the reversible part. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Zack--

The only info I have seen in the Isuzu manual for injector break pressure is 1493 for the n/a engine and 1920 for the turbo engine. Can you tell me where in the manual you see the other numbers? I would like to take a look.

I am using the turbo injectors (set at 1920) in my turbo truck as I got these when I got the turbo stuff. But I ran the n/a injectors for a while before and I can't say I noticed a difference when I changed over.

I think the higher break pressure will give a more forceful injection and probably a finer spray. And, for the turbo engine, it ensures that there is enough pressure to spray well into the higher cylinder pressures encountered.

I think you mentioned starting w/o glowing before. When my glow system is not working the engine is very hard to start, unless already warm. So, I am surprised that you seem to be doing this as a matter of course. Are you doing this cold and how long must you crank?

Paul

I cranked up the old injector to 2800 psi this morning, and it didn't spray any better. The injector need rebuilding.
I have a Isuzu Workshop Manual for the Pup diesel. On page 3-4 in the diagnostic section, it says fuel injection starting pressure is 1493 psi. The page opposite this one (the next one) has it as 1707 psi. Then on page 8-3 under the fuel section, it states injection starting pressure is 2133 psi.
Thanks for the info on the pressures and the un-obvious differences. At least I can expect little to no changes. If nothing else I can make sure they are at least up to one of the factory numbers.

First start in the morning definately needs glowing. If it stays about 20C or more all day (around 70F) then I can usually start without glowing at all, and it'll start after cranking a couple of seconds. This would be after work, about 9 hours of sitting. When the engine is warm, usually as fast as you can turn the key starts it. I also forgot to mention the funny start-stall-start-stall thing went away with the injector cleaning. Although it makes sense, I never would have guessed that a bit of crap around the injector hole could make such a dramatic difference.
Tomorrow I'm going to check the other 3 old injectors. Hopefully there's a good one or two in there.

Oh yea. Just for fun, I priced up new canola oil. A 16 liter pale is $21.99. That's under $1.38 a liter. Fuel here varies like everywhere, I paid $1.049\l last night for some. Too bad it's so much. Oh well.

Zack--

Well, OK on the glowing. My truck performs just about the same as yours. I got to thinking that you were able to start cold w/o glowing. <img src="/forums/images/graemlins/confused.gif" alt="" />

Re the injectors. I think that the spray pattern is the most important for good combustion. The exact break pressure is probably less important. Maybe higher pressures are better once the spray pattern is right. But there is a caveat to higher pressure. The injection pump works harder to achieve the higher pressures and therefore must consume more power from the engine. I don't know how significant this is.

Re your 'bad injectors'. These can be 'rebuilt' by going to your local fuel injection shop and buying new nozzle assemblies and installing them yourself and then resetting the break pressure. The nozzles are the same as used in the VW Rabbit/Jetta diesels and should not be too pricey.

Yeah, one could almost buy canola or other veggie oil at the current price of diesel. But, if your 'oil soup' brew is working OK then you have the best deal of all.

I have been paying about $3.10 US/ gal US. Must be pretty close to your price.

Paul

Edit: I checked my manuals and cannot find the entries you mention re injector break pressures. I think we must have different manuals. I have the Isuzu shop manuals for the '82, '84, '85 and '86 P'ups.